1. Field of the Invention
The present invention relates to an apparatus for sensing the presence or absence of an object in order to actuate a pneumatic circuit. In a preferred embodiment, the present invention is directed to an apparatus for detecting the presence or absence of a golf ball on a tee of an automatic golf ball teeing apparatus.
2. Discussion of the Prior Art
Numerous devices exist for detecting the presence or absence of an object in order to actuate a pneumatic circuit. Among these devices, is that disclosed in U.S. Pat. No. 5,348,305, to Lowe, the inventor of the present invention. The sensor system disclosed by Lowe is directed to the sensing of the presence or absence of a golf ball on a tee of an automatic golf ball teeing device. To achieve this automatic sensing function, whereby the pneumatic circuit engages an actuator for replacing a ball on the tee when the sensing circuit indicates the absence of a ball on the tee, a bore is disposed such that it is in fluidic communication with a central aperture of the tee. A non-contacting air limit switch assembly provides a continuous regulated sensing jet of air through a flexible conduit which is in fluidic communication with the bore and the central aperture of the tee. The sensing jet of air escapes through an open mouth of the hollow tee. The assembly includes a pressure regulator, a non-contacting air limit switch and a fluidic interface valve. When the sensing jet is uninterrupted by contact with a solid object, no supply air passes through the fluidic interface valve. Conversely, when the sensing jet is interrupted by the presence of a solid object, such as, for example, a golf ball coming to rest on the open mouth of the tee, the air supply passes through the interface valve of the pneumatic circuit. Upon passing through the interface valve, the air supply actuates a switch that causes the pneumatic reciprocation device to be engaged to place a golf ball on the vacant tee.
While the device disclosed by Lowe operates in an acceptable manner, there are numerous attendant disadvantages associated with the sensing configuration of the Lowe device. Among these disadvantages is the inefficient use of supply air. The Lowe device wastes excessive amounts of compressed air by having air escaping throughout the ball replacement process. Moreover, the sensing device of Lowe is unnecessarily complex. It is also important that the apparatus be capable of withstanding the shock force of an object striking the golf ball, such as, for example, a golf club. Having the air supply in fluidic contact with the tee may potentially render the prior system vulnerable to damage from the shock force of a club striking the ball and tee.